Former Captain Nasser Hussain has said that not only the left-hand opening batsman Alastair Cook was mentally the toughest, he was one of England greatest ever players too. Having made his debut against India at Nagpur in 2006, Cook announced that he'll be retiring from the game at the end of the ongoing series against Virat Kohli's men. 

Cook, certainly not a gifted batsman, exemplified what Test Cricket is all about. With his ability to defy the best of bowlers in his prime and survive for long periods of time, he has amassed 12,254 at an average of 44.88 across 160 Tests in a 13 years long career. Cook is the kind of person, if not marrying your daughter, you won't mind him scoring his last hundred against you for sure. 

"I am not that surprised that Cook has decided to retire, to be honest. Conditions for opening batsmen in England over the last few years have been so difficult." Nasser wrote in his column for Sky Sports, "After 160 Tests at the top of the order, facing a Dukes ball in most of those, there are only so many times that even the mentally-toughest cricketer I have ever seen - as far as England goes anyway - can go to that well, dig deep and try to summon up even more mental strength." 

"He never had a perfect technique so he has had to dig deep even more. He is constantly battling against his technique and when that new ball is darting around, he has to work hard to keep on top of his game. Batting doesn't always come naturally to him - but what has come naturally is how hard mentally he has had to work at it. With Alastair, it's also not just what you see but the stuff behind the scenes as well."

Nasser further wrote in his fitting tribute, "When he is not playing Test cricket he will be at Chelmsford in the nets working with the likes of Graham Gooch and Keith Fletcher to improve his game and then go to the gym. You don't play 158 Tests in a row without being supremely fit."

Nasser also shed light again on how brilliant Cook carried himself in the toughest of times and wrote, "I'd also like to say dignified he has been and how well he has carried himself. As a captain, you are not only a player but are also representing your country and sport. Even in his darkest moments, such as losing the Ashes 5-0, he has stood up, never complained and got on with his game. This country should be very proud of him."

"His biggest comeback, I think, was in the 2015 Ashes, after the whitewash in Australia [in 2013-14]. To win that series and then see him up on that podium - that was his redemption."

In conclusion, Nasser explained that eventually, England will find someone ripe to take Cook's place. 

"No one is irreplaceable - Sachin Tendulkar retired and people said there will be no one like that but Virat Kohli has come along. So eventually someone will come along but it will take some time to find another Cook." he wrote and added, "For him it was always about surviving, giving his best and never giving his wicket away, so the last thing Alastair will want is a couple of low scores at The Oval and people standing for him."

(Inputs from Sky Sports)